Laser radar lens and laser radar

Abstract

The invention discloses a laser radar lens and a laser radar. The laser radar lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object space to an image space along an optical axis. Each of the first lens to the sixth lens comprises an object side surface which faces the object space and allows imaging light to pass through and an image side surface which faces the image space and allows the imaging light to pass through; the first lens has negative diopter; the second lens has positive diopter; the third lens has negative diopter; the fourth lens has positive diopter; the fifth lens has positive diopter; and the sixth lens has positive diopter. According to the laser radar lens provided by the embodiment of the invention, a large target surface is realized under a relatively small f number, the cost is low, and the image quality is good.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lenses, and in particular to a laser radar lens and a laser radar. Background Art

[0002] In recent years, with the development of electronic technology, the application scope of cameras has become increasingly wider, and the optical lens used in automotive LiDAR is one of the key aspects. LiDAR transmits a detection signal to the target, and then the receiving lens set in front of the LiDAR detector focuses the reflected light onto the detector. After comparing the signal reflected from the target with the transmitted signal and performing appropriate processing, relevant information about the target, such as target distance, height, speed, and other parameters, can be obtained, thereby detecting, tracking, and identifying the target. However, existing LiDAR lenses have at least the following shortcomings:

[0003] 1. Existing products have a contradiction between cost and performance.

[0004] 2. Existing products cannot take into account both large aperture and large target area. Summary of the Invention

[0005] The embodiments of the present invention provide a laser radar lens and a laser radar, so as to realize a large target surface at a smaller f-number, with low cost and good image quality.

[0006] In a first aspect, an embodiment of the present invention provides a laser radar lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, arranged in sequence along an optical axis from an object side to an image side; each of the first to sixth lenses includes an object-side surface facing the object side and allowing imaging light to pass therethrough, and an image-side surface facing the image side and allowing imaging light to pass therethrough;

[0007] The first lens has negative refractive power;

[0008] The second lens has positive refractive power;

[0009] The third lens has negative refractive power;

[0010] The fourth lens has positive refractive power;

[0011] The fifth lens has positive refractive power;

[0012] The sixth lens has positive refractive power.

[0013] Optionally, the object side surface of the first lens is convex, and the image side surface of the first lens is concave; the object side surface of the second lens is convex; the object side surface of the third lens is concave, and the image side surface of the third lens is concave; the object side surface of the fourth lens is convex, and the image side surface of the fourth lens is convex; the image side surface of the fifth lens is concave, and the image side surface of the fifth lens is convex; the object side surface of the sixth lens is convex, and the image side surface of the sixth lens is concave.

[0014] Optionally, the thickness of the first lens on the optical axis is T1, and the refractive index of the first lens is nd1, satisfying:

[0015] 1.5<T1<1.941; and / or, nd1≥1.8.

[0016] Optionally, the refractive index of the third lens is nd3, and the refractive index of the fifth lens is nd5, satisfying:

[0017] nd3<1.6; and / or, nd5>1.7.

[0018] Optionally, the first lens to the sixth lens are all glass lenses.

[0019] Optionally, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6, satisfying:

[0020] 0.58<f2 / f1<0.6; and / or, 1<f6 / f5<1.1.

[0021] Optionally,

[0022]

[0023] Wherein, n6 is the refractive index of the sixth lens, EXP is the exit pupil diameter of the laser radar lens, R L2 is the curvature radius of the surface of the sixth lens close to the image plane.

[0024] Optionally,

[0025]

[0026] Wherein, D1 is the aperture of the first lens, which is the maximum diameter of the light it allows to pass through, and F # is the F number of the laser radar lens, EPD is the entrance pupil diameter of the laser radar lens, and FOV is the field of view angle of the laser radar lens.

[0027] Optionally,

[0028]

[0029] Among them, TTL is the total optical length of the laser radar lens, the total optical length is the distance from the center of the surface of the first lens close to the object plane to the image plane, CT4 is the center thickness of the fourth lens on the optical axis, CT5 is the center thickness of the fifth lens on the optical axis, and CT6 is the center thickness of the sixth lens on the optical axis.

[0030] In a second aspect, an embodiment of the present invention provides a laser radar, comprising a transmitting module and a receiving module, wherein the receiving module comprises the laser radar lens described in the first aspect.

[0031] The laser radar lens provided in this embodiment of the present invention consists of six lenses, with the refractive powers of the first lens 1 through the sixth lens 6 being negative, positive, negative, positive, positive, and positive, respectively. This laser radar lens consists of only the six lenses described above, and through the appropriate design of each lens, it achieves low cost and minimal diffuse spot, meeting the requirements of the laser radar receiver. This laser radar lens achieves a large target area at a low f-number, offering low cost and high image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a laser radar lens provided in an embodiment of the present invention;

[0033] Figure 2 This is an optical path diagram of the laser radar lens provided in Example 1 of the present invention;

[0034] Figure 3 A spot diagram provided in Example 1 of the present invention;

[0035] Figure 4 This is the MTF curve of the laser radar lens in Example 1 at room temperature and infrared 940nm;

[0036] Figure 5 This is the geometric energy encirclement diagram of the laser radar lens in Example 1;

[0037] Figure 6 An optical path diagram of the laser radar lens provided in the second embodiment of the present invention;

[0038] Figure 7 A spot diagram provided for the second embodiment of the present invention;

[0039] Figure 8 This is the MTF curve of the laser radar lens in Example 2 at room temperature and infrared 940nm;

[0040] Figure 9 This is the geometric energy encirclement diagram of the laser radar lens in Example 2;

[0041] Figure 10This is an optical path diagram of the laser radar lens provided in Example 3 of the present invention;

[0042] Figure 11 A spot diagram provided in the third embodiment of the present invention;

[0043] Figure 12 This is the MTF curve of the laser radar lens in Example 3 at room temperature and infrared 940nm;

[0044] Figure 13 This is the geometric energy encirclement diagram of the laser radar lens in Example 3. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0046] In this specification, the lens having positive refractive power (or negative refractive power) means that the paraxial refractive power of the lens calculated by Gaussian optical theory is positive (or negative). The object side (or image side) of the lens is defined as the specific range of the lens surface through which the imaging light passes. The convexity and concavity of the lens surface can be judged according to the judgment method of ordinary knowledge in this field, that is, the concavity and convexity of the lens surface can be judged by the positive and negative signs of the radius of curvature (abbreviated as R value). R value is also commonly found in the lens data sheet of optical design software. For the object side, when the R value is positive, the object side is judged to be convex; when the R value is negative, the object side is judged to be concave. Conversely, for the image side, when the R value is positive, the image side is judged to be concave; when the R value is negative, the image side is judged to be convex.

[0047] Figure 1 This is a schematic diagram of the structure of the laser radar lens provided in an embodiment of the present invention, refer to Figure 1 The LiDAR lens includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, and a sixth lens 6, arranged in sequence along the optical axis from the object side to the image side. Each of the first through sixth lenses includes an object-side surface facing the object side through which imaging light passes, and an image-side surface facing the image side through which imaging light passes. In other words, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 each include an object-side surface and an image-side surface. The first lens 1 has negative refractive power; the second lens 2 has positive refractive power; the third lens 3 has negative refractive power; the fourth lens 4 has positive refractive power; the fifth lens 5 has positive refractive power; and the sixth lens 6 has positive refractive power. Refractive power is optical focal length.

[0048] The laser radar lens provided in this embodiment of the present invention consists of six lenses, with the refractive powers of the first lens 1 through the sixth lens 6 being negative, positive, negative, positive, positive, and positive, respectively. This laser radar lens consists of only the six lenses described above, and through the appropriate design of each lens, it achieves low cost and minimal diffuse spot, meeting the requirements of the laser radar receiver. This laser radar lens achieves a large target area at a low f-number, offering low cost and high image quality.

[0049] Optionally, refer to Figure 1 The object-side surface of the first lens 1 is convex, and the image-side surface of the first lens 1 is concave, so the first lens 1 is a convex-concave lens; the object-side surface of the second lens 2 is convex; the object-side surface of the third lens 3 is concave, and the image-side surface of the third lens 3 is concave, so the third lens 3 is a biconcave lens; the object-side surface of the fourth lens 4 is convex, and the image-side surface of the fourth lens 4 is convex, so the fourth lens 4 is a biconvex lens; the image-side surface of the fifth lens 5 is concave, and the image-side surface of the fifth lens 5 is convex, so the fifth lens 5 is a convex-concave lens; the object-side surface of the sixth lens 6 is convex, and the image-side surface of the sixth lens 6 is concave, so the sixth lens 6 is a convex-concave lens. In this embodiment of the present invention, the imaging quality is improved by optimizing the surface shapes of the first lens 1 to the sixth lens 6.

[0050] Illustratively, the image-side surface of the second lens 2 includes, but is not limited to, a convex surface, a concave surface, or a flat surface.

[0051] Optionally, refer to Figure 1 The thickness of the first lens 1 on the optical axis is T1, which satisfies the following: 1.5<T1<1.941. This can control the total length of the laser radar lens, thereby reducing the cost of the laser radar lens.

[0052] Optionally, refer to Figure 1 , the refractive index of the first lens 1 is nd1, which satisfies: nd1 ≥ 1.8. The lens with the largest aperture in the laser radar lens is the first lens 1, and the aperture of the first lens 1 determines the aperture and outer diameter of the laser radar lens. When the field of view is fixed, a lens with a higher refractive index has a higher light deflection ability and can collect light; if the refractive index is not high enough, the aperture of the lens needs to be increased to collect light. Therefore, the embodiment of the present invention reduces the aperture of the first lens 1 by setting nd1 ≥ 1.8, which is conducive to reducing the aperture of the laser radar lens and reducing the outer diameter of the laser radar lens.

[0053] Optionally, refer to Figure 1 The refractive index of the third lens 3 is nd3, which satisfies: nd3<1.6. This reduces the cost of the laser radar lens.

[0054] Optionally, refer to Figure 1, the first lens 1 to the sixth lens 6 are all made of glass lenses. This reduces the production cost of the lidar lens. Since the first lens 1 to the sixth lens 6 are all made of glass, they have better reliability and dependability, a more stable structure, and are suitable for vehicle-mounted applications. Compared with glass lenses, plastic lenses are more susceptible to temperature effects, resulting in greater thermal expansion and contraction, leading to tolerance sensitivity. The embodiment of the present invention uses an all-glass lens, which has a small thermal expansion and contraction caused by temperature and is insensitive to tolerances.

[0055] Optionally, refer to Figure 1 , the focal length value of the first lens 1 is f1, and the focal length value of the second lens 2 is f2, satisfying: 0.58<f2 / f1<0.6. f2 is smaller than f1, and the light converging ability of the second lens 2 is stronger than that of the first lens 1. The refractive power of the first lens 1 is a negative value, and it is a concave lens. The diverging effect of the first lens 1 on the light needs to be converged by the second lens 2. Therefore, the light converging ability of the second lens 2 is set to be stronger than that of the first lens 1. Furthermore, by controlling the first lens 1 and the second lens 2 to have appropriate focal length values, the back focus offset of the lidar lens at high and low temperatures can be controlled.

[0056] Optionally, refer to Figure 1 , the focal length of the fifth lens 5 is f5, and the focal length of the sixth lens 6 is f6, satisfying: 1<f6 / f5<1.1. f6 is smaller than f5, and the light converging ability of the sixth lens 6 is weaker than that of the fifth lens 5. The sixth lens 6 is the last lens in the lidar lens. Reducing the light converging ability of the sixth lens 6 reduces the tolerance sensitivity of the sixth lens 6 and reduces the back focus offset of the lidar lens at high and low temperatures. Among them, the back focus offset refers to the deviation of the back focus of the lidar lens from the ideal position (or the design position) due to the thermal expansion and contraction of the lens due to temperature.

[0057] Optionally, refer to Figure 1 The refractive index of the fifth lens element 5 is nd5, where nd5 > 1.7. A higher refractive index increases the optical path length compared to air over the same distance. The optical path length is the product of the light propagation distance and the refractive index of the medium. To achieve the same optical path length, using a fifth lens element 5 with a higher refractive index can shorten the overall length of the LiDAR lens, thereby reducing its cost.

[0058] Optionally, refer to Figure 1 ,satisfy:

[0059]

[0060] Wherein, n6 is the refractive index of the sixth lens 6, EXP is the exit pupil diameter of the laser radar lens, R L2is the radius of curvature of the surface of the sixth lens 6 close to the image plane. The image plane corresponds to the image side, and the object plane corresponds to the object side. The exit pupil diameter is the diameter of the light beam emitted from the laser radar lens, and its unit is the unit of length. L2 The unit is the length unit. L2 The dimensions of EXP are the same, for example, millimeters. For the above conditional expression, the upper and lower limits ensure that the back focus and the incident angle of the main ray are within a reasonable range.

[0061] Optionally, refer to Figure 1 ,satisfy:

[0062]

[0063] Where D1 is the aperture of the first lens 1, which is the maximum diameter of the light it allows to pass through, and F # is the F number of the LiDAR lens, EPD is the entrance pupil diameter of the LiDAR lens, and FOV is the field of view angle of the LiDAR lens. The unit of D1 is length unit. F number, also known as aperture, is the ratio of the focal length of the LiDAR lens to the entrance pupil diameter. The unit of EPD is length unit. EPD and D1 have the same dimension, for example, both are millimeters. The unit of FOV is degree. For the above conditional formula, the aperture and image plane size of the LiDAR lens are guaranteed. Its upper limit limits the aperture of the LiDAR lens to an acceptable range, so that it is not too large and increases the volume of the entire LiDAR lens. Its lower limit ensures that the image plane size and entrance pupil diameter of the LiDAR lens meet the preset requirements and are adapted to the field of view angle, so that they are not too large or too small.

[0064] Optionally, refer to Figure 1 ,satisfy:

[0065]

[0066] Wherein, TTL is the total optical length of the lidar lens, which is the distance from the center of the surface of the first lens 1 closest to the object plane to the image plane. CT4 is the center thickness of the fourth lens along the optical axis, CT5 is the center thickness of the fifth lens along the optical axis, and CT6 is the center thickness of the sixth lens along the optical axis. In this application, the center thickness of each lens is the thickness of each lens along the optical axis. The units of TTL, CT4, CT5, and CT6 are length units. TL, CT4, CT5, and CT6 have the same dimension, for example, millimeters.

[0067] The upper limit of the above conditional expression limits the total optical length of the LiDAR lens and the combined thickness of the fourth lens 4, fifth lens 5, and sixth lens 6 to a certain ratio. Since the total optical length is limited by a preset value, and thicker lenses help reduce the LiDAR lens's field curvature, the fourth lens 4, fifth lens 5, and sixth lens 6 are appropriately thickened to reduce the LiDAR lens's field curvature. The lower limit is used to limit the thickness of the fourth lens 4, fifth lens 5, and sixth lens 6 to avoid excessive thickness. A reasonable thickness of the fourth lens 4, fifth lens 5, and sixth lens 6 allows space for other lenses and air gaps, facilitating the matching of lens materials and curvatures to better offset primary aberrations.

[0068] Illustratively, the laser radar lens of the present invention has the advantages of large aperture (working f-number less than or equal to 1.2), large target surface (chip diagonal length 9.677mm, image height greater than or equal to 4.8385mm), etc.

[0069] Exemplarily, the lidar lens further includes an aperture 9, a filter 7, and a protective sheet 8. The aperture 9 is disposed between the third lens 3 and the fourth lens 4. Of course, in other embodiments, the aperture 9 may be disposed in other suitable locations. The filter 7 is disposed between the sixth lens 6 and the protective sheet 8.

[0070] Example 1

[0071] Figure 2 The optical path diagram of the laser radar lens provided in the first embodiment of the present invention; Figure 1 and Figure 2 As shown, this embodiment discloses a laser radar lens, comprising, from the object side to the image side, first lens 1 to sixth lens 6, sequentially arranged along an optical axis. The first lens 1 has negative refractive power, with the object-side surface of the first lens 1 being convex and the image-side surface being concave. The second lens 2 has positive refractive power, with the object-side surface of the second lens 2 being convex. The third lens 3 has negative refractive power, with the object-side surface of the third lens 3 being concave and the image-side surface being concave. The fourth lens 4 has positive refractive power, with the object-side surface of the fourth lens 3 being convex and the image-side surface being convex. The fifth lens 5 has positive refractive power, with the image-side surface of the fifth lens 5 being concave and the image-side surface being convex. The sixth lens 6 has positive refractive power, with the object-side surface of the sixth lens 6 being convex and the image-side surface being concave. An aperture 9 is disposed between the third lens 3 and the fourth lens 4. Detailed optical data of this specific embodiment are shown in Table 1.

[0072] Table 1 Detailed optical data of Example 1

[0073] Surface number type curvature thickness Material Refractive index Abbe number focal length 0 Physical Surface Infinity 100000 1 First lens 26.115 1.5 Glass 1.80 46.6 -26.12 2 11.2623 2.953 3 Second lens 13.767 5.292 Glass 1.90 31.3 15.70 4 Infinity 1.894 5 The third lens -15.679 1.48 Glass 1.59 61.3 -11.78 6 12.487 2.309 7 aperture Infinity -0.102 8 Fourth lens 45.879 4.274 Glass 1.83 37.2 21.75 9 -27.802 2.515 10 Fifth lens -80.134 4.338 Glass 1.71 53.8 26.98 11 -15.477 0.155 12 Sixth lens 13.323 4.401 Glass 1.90 31.3 30.11 13 22.725 7.534 14 Filters Infinity 0.55 Filters 1.52 64.2 15 1.7 16 Protective glass Infinity Glass 1.52 64.2 17 18 IMA

[0074] Table 1 shows the detailed optical data of Example 1, and its specific numerical values ​​can be adjusted according to product requirements and are not limitations of the embodiments of the present invention. A lens generally includes two surfaces, each of which is a refractive surface. The surface numbers in Table 1 are numbered according to the surfaces of each lens. Among them, surface number 0 represents the object surface. Surface number 1 represents the front surface of the first lens 1 (i.e., the object side surface), surface number 2 represents the back surface of the first lens 1 (i.e., the image side surface), and so on, which are not repeated here. The type IMA corresponding to surface number 18 represents the image surface. The radius of curvature represents the degree of curvature of the lens surface. A positive radius of curvature value indicates that the center of curvature is on the side of the surface close to the image side, and a negative radius of curvature value indicates that the center of curvature is on the side of the surface away from the image side. The unit of the radius of curvature is mm. Infinity in the radius of curvature column indicates that the surface is a plane. The value in the thickness column represents the axial distance from the current surface to the next surface. The unit of thickness is mm. The unit of focal length is mm.

[0075] In this specific embodiment, the focal length of the laser radar lens is f=11.64mm, the aperture value is FNO=1.2, the field of view angle FOV=52°, and the half image height IMH is between 4.8385 and 4.905mm, so that the target surface of the sensor can be filled (the chip diagonal length is 9.677mm, and half of 9.677mm is 4.8385mm). In one example, the half image height IMH=4.905mm, and the total length TTL=41mm. When the half image height IMH is greater than half of the chip diagonal length, a certain margin can be set for assembly error. Prevent the laser radar lens and the chip from being offset due to assembly error. Among them, the chip is the sensor, and the light-receiving surface of the chip is the target surface of the sensor. The laser radar lens can achieve a large target surface at a smaller f-number.

[0076] Figure 3 The point diagram provided in the first embodiment of the present invention is as follows: Figure 3 It can be seen that the full field of view point diagram is less than 12um, with small aberration and good imaging quality.

[0077] Figure 4 This is the MTF curve of the laser radar lens in Example 1 at room temperature and infrared 940nm. Figure 4 This demonstrates the high performance of the LiDAR lens using a 30μm pixel sensor. A vertical axis greater than 0.2 is just discernible to the human eye. In this embodiment, the OTF modulus is greater than 0.7, significantly greater than 0.2, indicating excellent imaging quality.

[0078] Figure 5 The geometric energy encirclement diagram of the laser radar lens in Example 1 is shown in FIG. Figure 5 , the full field of view at 15μm encompasses nearly 90% of the energy.

[0079] Example 2

[0080] Figure 6 This is an optical path diagram of the lidar lens provided in Example 2 of the present invention. The surface profile and diopter of each lens in this embodiment are roughly the same as those in Example 1, but optical parameters such as the radius of curvature and lens thickness differ. Similarities with the above-mentioned embodiments are not repeated here.

[0081] The detailed optical data of this specific embodiment are shown in Table 2.

[0082] Table 2 Detailed optical data of Example 2

[0083] Surface number type curvature thickness Material Refractive index Abbe number focal length 0 Physical Surface Infinity 100000 1 First lens 25.689 1.858 Glass 1.80 46.6 -26.6 2 11.242 2.987 3 Second lens 13.448 4.522 Glass 1.90 31.3 15.5 4 978.425 1.909 5 The third lens -16.979 1.556 Glass 1.59 61.3 -11.79 6 11.803 2.484 7 aperture Infinity -0.102 8 Fourth lens 46.694 4.519 Glass 1.83 37.2 21.76 9 -27.267 3.011 10 Fifth lens -57.681 4.176 Glass 1.71 53.8 28.35 11 -15.197 0.164 12 Sixth lens 13.161 4.434 Glass 1.90 31.3 28.78 13 23.153 7.28 14 Filters Infinity 0.55 Filters 1.52 64.2 15 Infinity 1.7 16 Protective glass Infinity 0.3 Glass 1.52 64.2 17 Infinity 0 18 IMA

[0084] In this specific embodiment, the focal length of the laser radar lens is f=11.55 mm, the aperture value is FNO=1.2, the field of view angle FOV=52°, the half image height IMH=4.905 mm, and the total length TTL=41 mm.

[0085] Figure 7 The point diagram provided by the second embodiment of the present invention is as follows: Figure 7 It can be seen that the full field of view point diagram is less than 12um, with small aberration and good imaging quality.

[0086] Figure 8 This is the MTF curve of the laser radar lens in Example 2 at room temperature and infrared 940nm. Figure 8 This shows that the lidar lens exhibits high performance under the conditions of the selected 30μm pixel sensor.

[0087] Figure 9 The geometric energy encirclement diagram of the laser radar lens in Example 2 is shown in FIG. Figure 9 , the full field of view at 15μm encompasses nearly 90% of the energy.

[0088] Example 3

[0089] Figure 10 This is an optical path diagram of the lidar lens provided in Example 3 of the present invention. The surface profile and diopter of each lens in this embodiment are roughly the same as those in Example 1, but optical parameters such as the radius of curvature and lens thickness differ. Similarities with the above-mentioned embodiments are not repeated here.

[0090] The detailed optical data of this specific embodiment are shown in Table 3.

[0091] Table 3 Detailed optical data of Example 3

[0092] Surface number type curvature thickness Material Refractive index Abbe number focal length 0 Physical Surface Infinity 100000 1 First lens 26.782 1.941 Glass 1.80 46.6 -26.39 2 11.328 2.992 3 Second lens 13.45 5.482 Glass 1.90 31.3 15.59 4 -2372.321 1.71 5 The third lens -17.397 1.47 Glass 1.59 61.3 -11.85 6 11.691 2.503 7 aperture Infinity -0.128 8 Fourth lens 47.612 4.639 Glass 1.83 37.2 21.79 9 -26.995 3.042 10 Fifth lens -57.899 4.621 Glass 1.71 53.8 28.17 11 -15.185 0.173 12 Sixth lens 13.069 4.443 Glass 1.90 31.3 28.94 13 22.641 7.266 14 Filters Infinity 0.55 Filters 1.52 64.2 15 Infinity 1.7 16 Protective glass Infinity 0.3 Glass 1.52 64.2 17 Infinity 0 18 IMA

[0093] In this specific embodiment, the focal length of the laser radar lens is f=11.57 mm, the aperture value is FNO=1.2, the field of view angle FOV=52°, the half image height IMH=4.905 mm, and the total length TTL=42.7 mm.

[0094] Figure 11 The point diagram provided by the third embodiment of the present invention is as follows: Figure 11 It can be seen that the full field of view point diagram is less than 12um, with small aberration and good imaging quality.

[0095] Figure 12 This is the MTF curve of the laser radar lens in Example 3 at room temperature and infrared 940nm. Figure 12 This shows that the lidar lens exhibits high performance under the conditions of the selected 30μm pixel sensor.

[0096] Figure 13 The geometric energy encirclement diagram of the laser radar lens in Example 3 is shown in Figure 2. Figure 13 , the full field of view at 15μm encompasses nearly 90% of the energy.

[0097] An embodiment of the present invention further provides a laser radar, comprising a transmitting module and a receiving module, wherein the receiving module includes the laser radar lens of the above embodiment. This achieves the beneficial effects of the laser radar lens of the above embodiment, namely, achieving a large target area at a small f-number, low cost, and good image quality.

[0098] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations, and substitutions are possible for those skilled in the art without departing from the scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A laser radar lens, characterized in that: The invention comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in sequence from the object side to the image side along the optical axis; the first lens to the sixth lens each include an object-side surface facing the object side and allowing imaging light to pass therethrough, and an image-side surface facing the image side and allowing imaging light to pass therethrough; The first lens has negative refractive power; The second lens has positive refractive power; The third lens has negative refractive power; The fourth lens has positive refractive power; The fifth lens has positive refractive power; The sixth lens has positive refractive power.

2. The laser radar lens according to claim 1, characterized in that: The object-side surface of the first lens is convex, and the image-side surface of the first lens is concave; the object-side surface of the second lens is convex; the object-side surface of the third lens is concave, and the image-side surface of the third lens is concave; the object-side surface of the fourth lens is convex, and the image-side surface of the fourth lens is convex; the image-side surface of the fifth lens is concave, and the image-side surface of the fifth lens is convex; the object-side surface of the sixth lens is convex, and the image-side surface of the sixth lens is concave.

3. The laser radar lens according to claim 1, characterized in that The thickness of the first lens on the optical axis is T1, and the refractive index of the first lens is nd1, which satisfies: 1.5<T1<1.941; and / or, nd1≥1.

8.

4. The laser radar lens according to claim 1, characterized in that The refractive index of the third lens is nd3, and the refractive index of the fifth lens is nd5, satisfying: nd3<1.6; and / or, nd5>1.

7.

5. The laser radar lens according to claim 1, characterized in that: The first lens to the sixth lens are all glass lenses.

6. The laser radar lens according to claim 1, characterized in that: The focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6, satisfying: 0.58<f2 / f1<0.6; and / or, 1<f6 / f5<1.

1.

7. The laser radar lens according to claim 1, characterized in that: Wherein, n6 is the refractive index of the sixth lens, EXP is the exit pupil diameter of the laser radar lens, R L2 is the curvature radius of the surface of the sixth lens close to the image plane.

8. The laser radar lens according to claim 1, characterized in that: Wherein, D1 is the aperture of the first lens, which is the maximum diameter of the light it allows to pass through, and F # is the F number of the laser radar lens, EPD is the entrance pupil diameter of the laser radar lens, and FOV is the field of view angle of the laser radar lens.

9. The laser radar lens according to claim 1, characterized in that: Among them, TTL is the total optical length of the laser radar lens, the total optical length is the distance from the center of the surface of the first lens close to the object plane to the image plane, CT4 is the center thickness of the fourth lens on the optical axis, CT5 is the center thickness of the fifth lens on the optical axis, and CT6 is the center thickness of the sixth lens on the optical axis.

10. A laser radar, characterized in that: It comprises a transmitting module and a receiving module, and the receiving module comprises the laser radar lens according to any one of claims 1 to 9.

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